Signal sampling using flex circuits on direct inter-connects

ABSTRACT

A method and system for sampling data signals between electronic components are provided. The invention comprises using a straight feed-through connector to connect electronic components and attaching one end of a flexible circuit to the pins of the feed-through connector. The other end of the flexible circuit is attached to a display, such as a LED. The display constitutes a field replaceable unit (FRU), which allows a malfunctioning display (i.e. LED) to be replaced without having to remove other electronic components. The present invention can be used for the detection of fault signals, status, idle signals, error checking, and introduction of a signal analyzer.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates to signal sampling betweencomponents in a computer system.

[0003] 2. Description of Related Art

[0004] Disk drive attachment to a motherboard, using the industrystandard Single Connector Attachment (SCA), will not allow for signalsampling and/or redirection of signals to Light Emitting Diode (LED)indicators. Drive integration and the use of various drive vendors haspresented an issue of access to LED indicator signals from drive optionblock connectors. Some vendors are eliminating the option blockconnectors from their designs.

[0005] Current practice is to use two connectors with a flex circuit tobridge between the drive and the motherboard, and use a third connector,on the flex circuit, to connect to the drive's option block. Withhigh-speed signals, such as Fiber channel 2 gigabits/sec, the multipleconnectors and flex circuits solution presents impedance and capacitanceclumping issues. Each connection has a capacitance. If the connectingflex is short, the two capacitances can clump together and reflect thesignal. Lengthening the flex will reduce capacitance clumping but willalso increase resistance and signal loss in the flex. Higher cost andlower reliability are also result from the two-connector solution.

[0006] Another approach has been to place LEDs on the motherboard orbackplane and use light pipes on the Field Replaceable Units (FRUs). Thelight pipes are used to convey activity and failure indicators from theLEDs. Unfortunately, this introduces reliability and servicing problemsrelated to the backplane. To replace a defective LED, the backplanewould have to be removed, resulting in the whole machine being takendown.

SUMMARY OF THE INVENTION

[0007] The present invention provides a method and system for samplingdata signals between electronic components. The invention comprisesusing a straight feed-through connector to connect electronic componentsand attaching one end of a flexible circuit to the pins of thefeed-through connector. The other end of the flexible circuit isattached to a display, such as a LED. The display constitutes a fieldreplaceable unit (FRU), which allows a malfunctioning display (i.e. LED)to be replaced without having to remove other electronic components orinterrupt machine availability. The present invention can be used forthe detection of fault signals, status, idle signals, error checking,and introduction of a signal analyzer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The novel features believed characteristic of the invention areset forth in the appended claims. The invention itself, however, as wellas a preferred mode of use, further objectives and advantages thereof,will best be understood by reference to the following detaileddescription of an illustrative embodiment when read in conjunction withthe accompanying drawings, wherein:

[0009]FIG. 1 depicts a pictorial representation of a data processingsystem in which the present invention may be implemented in accordancewith a preferred embodiment of the present invention;

[0010]FIG. 2 depicts a block diagram of a data processing system inwhich the present invention may be implemented;

[0011]FIGS. 3A-3C depict schematic diagrams illustrating three examplesof RAID systems in which the present invention may be implemented;

[0012]FIG. 4 depicts a schematic diagram illustrating the use of a flexcircuit to connect components in accordance with the prior art;

[0013]FIG. 5A depicts a schematic diagram illustrating signal samplingin accordance with the present invention;

[0014]FIG. 5B depicts a diagram illustrating the T concept underlyingthe signal tap method of the present invention;

[0015]FIG. 6A depicts a perspective view pictorial diagram illustratingthe flex circuit carrying the signal tap in accordance with the presentinvention;

[0016]FIG. 6B depicts a schematic diagram illustrating the flex circuitin accordance with the present invention;

[0017]FIG. 7 depicts a schematic diagram illustrating a unidirectionallocking tine in accordance with the present invention; and

[0018]FIG. 8 depicts a perspective view pictorial diagram illustrating adrive module with interposer flex, circuit inserted in the motherboard,in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] With reference now to the figures and in particular withreference to FIG. 1, a pictorial representation of a data processingsystem in which the present invention may be implemented is depicted inaccordance with a preferred embodiment of the present invention. Acomputer 100 is depicted which includes a system unit 110, a videodisplay terminal 102, a keyboard 104, storage devices 108, which mayinclude floppy drives and other types of permanent and removable storagemedia, and mouse 106. Additional input devices may be included withpersonal computer 100, such as, for example, a joystick, touchpad, touchscreen, trackball, microphone, and the like. Computer 100 can beimplemented using any suitable computer, such as an IBM RS/6000 computeror IntelliStation computer, which are products of International BusinessMachines Corporation, located in Armonk, N.Y. Although the depictedrepresentation shows a computer, other embodiments of the presentinvention may be implemented in other types of data processing systems,such as a network computer or Redundant Array of Independent Disks(RAID) system. Computer 100 also preferably includes a graphical userinterface that may be implemented by means of systems software residingin computer readable media in operation within computer 100.

[0020] With reference now to FIG. 2, a block diagram of a dataprocessing system is shown in which the present invention may beimplemented. Data processing system 200 is an example of a computer,such as computer 100 in FIG. 1, in which code or instructionsimplementing the processes of the present invention may be located. Dataprocessing system 200 employs a peripheral component interconnect (PCI)local bus architecture. Although the depicted example employs a PCI bus,other bus architectures such as Accelerated Graphics Port (AGP) andIndustry Standard Architecture (ISA) may be used. Processor 202 and mainmemory 204 are connected to PCI local bus 206 through PCI bridge 208.PCI bridge 208 also may include an integrated memory controller andcache memory for processor 202. Additional connections to PCI local bus206 may be made through direct component interconnection or throughadd-in boards. In the depicted example, local area network (LAN) adapter210, small computer system interface SCSI host bus adapter 212, andexpansion bus interface 214 are connected to PCI local bus 206 by directcomponent connection. In contrast, audio adapter 216, graphics adapter218, and audio/video adapter 219 are connected to PCI local bus 206 byadd-in boards inserted into expansion slots. Expansion bus interface 214provides a connection for a keyboard and mouse adapter 220, modem 222,and additional memory 224. SCSI host bus adapter 212 provides aconnection for hard disk drive 226, tape drive 228, and CD-ROM drive230. Typical PCI local bus implementations will support three or fourPCI expansion slots or add-in connectors. The present invention can beimplemented at any one of these interconnections.

[0021] Those of ordinary skill in the art will appreciate that thehardware in FIG. 2 may vary depending on the implementation. Otherinternal hardware or peripheral devices, such as flash ROM (orequivalent nonvolatile memory) or optical disk drives and the like, maybe used in addition to or in place of the hardware depicted in FIG. 2.Also, the processes of the present invention may be applied to amultiprocessor data processing system.

[0022] For example, data processing system 200, if optionally configuredas a network computer, may not include SCSI host bus adapter 212, harddisk drive 226, tape drive 228, and CD-ROM 230, as noted by dotted line232 in FIG. 2 denoting optional inclusion. In that case, the computer,to be properly called a client computer, must include some type ofnetwork communication interface, such as LAN adapter 210, modem 222, orthe like. As another example, data processing system 200 may be astand-alone system configured to be bootable without relying on sometype of network communication interface, whether or not data processingsystem 200 comprises some type of network communication interface. As afurther example, data processing system 200 may be a personal digitalassistant (PDA), which is configured with ROM and/or flash ROM toprovide non-volatile memory for storing operating system files and/oruser-generated data.

[0023] The depicted example in FIG. 2 and above-described examples arenot meant to imply architectural limitations. For example, dataprocessing system 200 also may be a notebook computer or hand heldcomputer in addition to taking the form of a PDA. Data processing system200/also may be a kiosk or a Web appliance.

[0024] Turning to FIGS. 3A-3C, schematic diagrams illustrating threeexamples of RAID systems in which the present invention may beimplemented are depicted in accordance with one embodiment of thepresent invention. RAID is a disk subsystem that increases performanceand/or provides fault tolerance, and is comprised of a set of two ormore hard disks and a specialized disk controller that contains the RAIDfunctionality. Developed initially for servers and stand-alone diskstorage systems, RAID is increasingly becoming available in desktop PCs,primarily for fault tolerance.

[0025] RAID improves performance by disk striping, which interleavesbytes or groups of bytes across multiple drives, so more than one diskis reading and writing simultaneously. Fault tolerance is achieved bymirroring or parity. Mirroring is 100% duplication of the data on twodrives, and parity calculates the data in two drives and stores theresult on a third drive. A failed drive can be hot swapped with a newone, and the RAID controller automatically rebuilds the lost data.

[0026] RAID 300 is an example of disk striping only, which interleavesdata across multiple disks for better performance. However, thisapproach does not provide safeguards against failure. RAID 301 employsdisk mirroring, which provides 100% duplication of data. This approachoffers the highest reliability, but doubles storage costs. RAID 302employs data striping across three or more drives for performance andparity bits for fault tolerance. The parity bits from two drives arestored on a third drive. This is the most widely used approach to RAIDsystems. The present invention can be used with any of the example RAIDapproaches described above, as well as other types of RAIDconfigurations.

[0027] Referring to FIG. 4, a schematic diagram illustrating the use ofa flex circuit to connect components is depicted in accordance with theprior art. The prior art approach is to use a flex circuit 403 toconnect components 401 and 402, with a separate branch 404 leading tothe LED. There are two contact points 405 and 406, at each end of theflex 403. This prior art approach has the disadvantage of increasedsignal length and added resistance due to the flex, as well as theresistance created by multiple contact points 405 and 406.

[0028] Referring to FIG. 5A, a schematic diagram illustrating signalsampling is depicted in accordance with the present invention. Twocomponents 501 and 502 are connected with a straight feed-throughconnector 504. An example of such a feed-through connector is the Molexinterposer connector. The feed-through connector and the introduction ofa flex circuit 503 reduces the number of contact points. By eliminatingflex 403, the signal length is reduced and the resistance created byflex 403 is eliminated. In addition, since the Molex connector is astraight feed-through connector, the electrical factors of impedance andcapacitive clumping are considerably reduced. The signal sampling methodin the present invention represents a “T” concept, which is illustratedin FIG. 5B. Signals a, b, and c represent the primary signals travelingbetween components 501 and 502. Signals d and e represents the tap,which is redirected along the Flex 503. The sampling and/or redirectionof signals can be accomplished as needed for LED indicators. The presentinvention can be used to sample data signals from any kind of hardwareconnection.

[0029] Referring now to FIG. 6A, a perspective view pictorial diagramillustrating the flex circuit carrying the signal tap is depicted inaccordance with the present invention. The flex 601 is held between thesnap fit halves 603 and 604 of the connector 600. The flex is attachedto the connector pins during assembly and a relief in the side of theconnector 600 allows for the escape of the flex circuit 601. The flexcircuit would be routed to a location on the drive FRU that would permitvisibility of the LED indicators 602.

[0030] In reference to FIG. 6B, a schematic diagram illustrating theflex circuit 601 is depicted in accordance with the present invention.Flex circuit 601 contains several openings 605 through which pins fromconnector 600 can pass and establish a connection between connector 600and flex 601. The flex 601 can be connected to the pins by severalmethods, such as, for example, soldering, wire trap, or unidirectionallocking tine.

[0031] Referring to FIG. 7, a schematic diagram illustrating aunidirectional locking tine is depicted in accordance with the presentinvention. The locking tines 702 are located in the opening 605 on theflex 601. The connector pins 701 are pushed through openings 605 in thedirection indicated by the arrow. The locking tine 702 applies enoughpressure against pin 701 to remove any gas barrier between the tine 702and pin 701 that might interfere with the conduction of an electricalcurrent. The shape of the tine 702 and the pressure exerted by it allowthe pin 701 to move only in the direction of insertion, indicated by thearrow. The stop block support 703 counters the pressure exerted by thetines 702 and maintains the proper parallel alignment between connectorpins 701.

[0032] Referring to FIG. 8, a perspective view pictorial diagramillustrating a drive module with interposer flex circuit inserted in themotherboard is depicted in accordance with the present invention. Thedrive 801 is installed in computer chassis 800. The flex circuit 601runs from the interposer connector 600, under the drive 801, to the LEDs602. By placing the LEDs 602 on the FRU, active components are removedfrom the motherboard 802 (or backplane), improving reliability andavoiding a servicing issue when an LED stops working. Thus, if an LED602 fails, it can be serviced without having to remove motherboard 802and interrupt the availability of the machine.

[0033] Data sampling has several applications including, for example,detection of fault signals, LED/status, idle signals, error checking, orintroduction of a signal analyzer.

[0034] The description of the present invention has been presented forpurposes of illustration and description, and is not intended to beexhaustive or limited to the invention in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art. The embodiment was chosen and described in order to bestexplain the principles of the invention, the practical application, andto enable others of ordinary skill in the art to understand theinvention for various embodiments with various modifications as aresuited to the particular use contemplated.

1-14. (canceled)
 15. A method for sampling data signals betweenelectronic components, comprising: connecting the electronic componentsby using a hardware connector; attaching one end of a flexible circuitto the hardware connector; and attaching an opposite end of the flexiblecircuit to an output device.
 16. The method according to claim 15,wherein the flexible circuit is attached to the hardware connector by aunidirectional locking tine.
 17. The method according to claim 15,wherein the flexible circuit is attached to the hardware connector by awire trap.
 18. The method according to claim 15, wherein the outputdevice is a light emitting diode.
 19. The method according to claim 15,wherein the output device constitutes a field replaceable unit.
 20. Themethod according to claim 15, wherein the hardware connector is afeed-through connector.
 21. The method according to claim 15, whereinthe data sampling can be used for detection of at least one of faultsignals, status, idle signals, error checking, and introduction of asignal analyzer.
 22. The method according to claim 15, whereinconnecting the components using a hardware connector includes: directlyconnecting a first electronic component to a first end of the hardwareconnector; and directly connecting a second electronic component to asecond end of the hardware connector, and wherein the flexible circuitis directly coupled to the hardware connector.
 23. The method accordingto claim 22, wherein the first electronic component is a storage deviceand the second electronic component is a circuit board.
 24. A system forsampling data signals between electronic components, comprising: ahardware connector for connecting the electronic components; firstattaching means for attaching one end of a flexible circuit to thehardware connector; and second attaching means for attaching theopposite end of the flexible circuit to an output device.
 25. The systemaccording to claim 24, wherein the flexible circuit is attached to thehardware connector by a unidirectional locking tine.
 26. The systemaccording to claim 24, wherein the flexible circuit is attached to thehardware connector by a wire trap.
 27. The system according to claim 24,wherein the hardware connector is a feed-through connector.
 28. Thesystem according to claim 24, wherein the data sampling can be used fordetection of at least one of fault signals, status, idle signals, errorchecking, and introduction of a signal analyzer.
 29. The systemaccording to claim 24, wherein a first end of the hardware connector isdirectly connected to a first electronic component and a second end ofthe hardware connector is directly coupled to a second electroniccomponent, and wherein the flexible circuit is directly coupled to thehardware connector.
 30. The system according to claim 29, wherein thefirst electronic component is a storage device and the second electroniccomponent is a circuit board.
 31. A method for sampling data signalsbetween a drive and a motherboard, comprising: providing a directconnection between the drive and the motherboard by way of an hardwareconnector; coupling a first end of a flexible circuit to the hardwareconnector; and coupling a second end of the flexible circuit to anindicator.
 32. The method of claim 31, wherein the first end of theflexible circuit is held between two snap-fit halves of the hardwareconnector.
 33. The method of claim 31, wherein the first end of theflexible circuit is coupled to the hardware connector by one of wiretaps and unidirectional locking tines.
 34. The method of claim 31,wherein the hardware connector is an interposer connector.